1. Field of the Invention
The breakaway mount is an intermediary coupling means for attaching a tool, such as a welding torch, to a robot or other form of automated machine equipment. The breakaway mount serves as a safety device for protection of the tool, the automated machine and the workpiece in the event of an unexpected collision of the tool with the workpiece. In the preferred embodiment, the breakaway mount connects to a welding torch on one end and releasably connects to an automated welding machine on the other end. In the event of an unexpected collision between the welding torch and the workpiece, the breakaway mount is designed to breakaway from the automated machine to prevent damage to the torch, the automated machine and/or the workpiece. Sensors can be incorporated in the breakaway mount to shut down the automated machine in the event of a collision.
2. Description of the Prior Art
The general concept of an intermediary safety device between a tool and an automated machine is well known in the prior art. Safety devices take various forms such as the ball and socket joint disclosed in U.S. Pat. No. 4,673,329 and other types of joints which are able to articulate in the event of a collision, such as U.S. Pat. No. 4,514,616. These types of devices swivel or tilt in response to a collision, but are not free to breakaway from the automated machine. Other devices such as U.S. Pat. Nos. 4,639,184, 4,655,674, and 4,741,642 rely upon a spring mechanism to absorb the shock of a collision; however, none of these devices have the ability to breakaway from the automated machine.
Most prior art safety devices rely upon switches or other sensing means to stop the robot or automated machinery in the event of a collision; however, due to the increased operating speeds of automated machinery and the increased momentum of the tools, some collisions are so catastrophic that the switches and other disconnect means cannot react fast enough to prevent damage. In some situations, a breakaway mount is essential for protection of the tool, the automatic machine, and the workpiece.
U.S. Pat. No. 4,725,190 discloses a mount which is capable of breaking away from an automated machine and represents an advancement in the art of intermediary safety coupling devices. In this patent, the base plate forms a receptacle which is contoured to receive a conical pin which protrudes from the breakaway mount. The pin is engaged by a releasable gripping mechanism which is spring-loaded. This type of breakaway mount will protect the tools, the automated machinery and the workpiece even in the event of a catastrophic collision.
If such a collision occurs, the breakaway mount must be manually re-engaged with the base plate. Because of the powerful spring-loaded nature of the gripping mechanism, closure of the mount with the baseplate occurs in a quick snap action. If the operator is not being particularly attentive when he re-engages the mount with the baseplate, the snap action closure can pinch any portion of the hand which is caught between the mount and the baseplate. The breakaway mount disclosed in U.S. Pat. No. 4,725,190 provides significant protection to the automated machinery and the workpiece; however, the nature of the closure mechanism does not provide similar protection to the operator when the mount is manually re-engaged with the baseplate.
Binzel of West Germany also manufactures a breakaway mount with a snap action closure. Photographs of the Binzel apparatus are included in the Information Disclosure Statement. Binzel likewise operates with a powerful spring-loaded gripping mechanism which is roughly equivalent to that disclosed in U.S. Pat. No. 4,725,190. Binzel therefore has all of the disadvantages of the aforementioned patent.
The present invention discloses a breakaway mount for robotic or automatic machines which is safer than prior art devices from the standpoint of the operator who manually re-engages the mount with the baseplate. In the preferred embodiment, the present invention uses a two-step pneumatic closure mechanism which provides a greater degree of safety to the operator during the re-engagement process. This two-step mode of attachment of the mount to the baseplate gives the operator the opportunity to move his hand away from the apparatus before the two parts are forcefully driven together by a double-acting piston cylinder arrangement.
In an alternative embodiment, the present invention uses a manually operated screw to gradually attach the mount to the baseplate. This embodiment likewise provides more safety to the operator than prior art designs. This mode of attachment is rather gradual and therefore, the operator likewise has the opportunity to remove his hand to avoid injury.
In either of the aforementioned embodiments, the breakaway mount can also include sensing means to stop operation of the machinery when complete or partial detachment of the mount occurs. As previously noted, these sensory means sometimes do not react quick enough and therefore the breakaway feature provides further safety to the machinery.